1. Field of the Invention
The present invention relates to an X-ray examination apparatus which is tiltable and pivotable about perpendicular axes passing through a body or object being examined.
2. The Prior Art
Devices for selectively adjusting the position of X-ray sources and image receivers with respect to the body of a patient remaining in a fixed position have become recognized as having substantial advantages over devices wherein the patient was moved with respect to fixed X-ray apparatus. The newer devices are particularly useful in surgical situations and in new body scanning applications wherein transverse sections of the body may be examined with computer analysis of multiple X-ray transmissions through the section.
An X-ray examination apparatus is known in which an X-ray tube and an X-ray image intensifier are mounted on opposite ends of a carrier member having a semicircular bend or arcuate curvature. The carrier is supported in a support mounting to be movable or displaceable along its circumference in a vertical plane and is also pivotally mounted for tilting its plane about a horizontal axis lying in the plane of the carrier and passing through the center of the semicircle. In this apparatus, the central ray of the X-ray tube always passes through the center of the semicircle regardless of tilting of the carrier plane or displacement of the carrier along its circumference in the support mounting. Simultaneous examination of a patient on a table using two such X-ray apparatuses in two different planes of the body is, however, usually impossible because of interference between the two sets of apparatus. In addition, adjustment of the X-ray tube and receiver is restricted by the mounting of the parts directly on the curved carrier. For example, adjustment of the X-ray tube by pushing the carrier in the direction of its curvature is not possible, but rather the entire carrier must be moved.
Other apparatus is known having a semicircular carrier with an X-ray tube and an image receiver mounted on extension arms fixed thereto and extending from one side of the plane of the carrier. Such apparatus permits positioning of two such devices so that the central rays of the two devices intersect at a right angle without interference between the sets of apparatus. In such devices, however, the adjustment range of the radiation source and image receiver is restricted to approximately 45.degree. in each direction from a vertical, middle position because the center of the carrier is not open but rather is obstructed by the supporting parts. Such prior apparatus cannot be used in a horizontal position without further swiveling of the holder itself.
Thus, it is desirable to provide an X-ray examination apparatus having an enlarged adjustment range.